Methods are known for the production of 4-bromothioanisole, for example, (1) the method comprising reacting thioanisole with bromine, followed by purification using a flash column (J. Amer. Chem. Soc., 119, 11381 (1997)), and (2) the method comprising reacting p-dibromobenzene with methanethiol copper salt (J. Amer. Chem. Soc., 90, 4051 (1968)).
As for method (1), however, it is difficult to separate the desired product 4-bromothioanisole from the byproduct 2-bromothioanisole, hence the purity of the desired product is low. As regards method (2), the yield is low, and copper-containing wastewater is generated, producing an environmental problem.